The present invention is related to devices and methods for determining the fill level of at least one coin tube that can be filled with coins. Moreover, the invention is related to a coin storage device for storing and/or paying out coins.
Moneychangers, for instance, have normally so-called coin tubes, in which coins stored in the moneychanger and to be paid out by the moneychanger are stored to be stacked atop of each other. One separate coin tube is provided for each type of coin. Thus, there is the necessity to determine the number of coins in the coin tubes, that is to say the fill level of the coin tubes, during the operation. It is known to achieve this by providing one or several light barriers, which are interrupted by the coin stack when one or several limit heights in the coin tubes are exceeded. It is disadvantageous in this kind of fill level determination that only discrete values of the fill level can be determined. In case that the coin stack is between two light barriers in its height, the coins between the light barriers are not included. Thus, this technology does not always offer sufficient accuracy in practice.
Moreover, the utilization of sound- or ultrasound sensors is known for the indicated purpose, which measure the elapsed time of an ultrasound signal from a sender to the uppermost coin of a coin stack and back from there to a receiver. By means of this measurement of the elapsed time, the distance between the ultrasound sensor or receiver and the uppermost coin is calculated, from which—with known coin thickness—the height of the coin stack and thus the number of coins which are in the coin tube can be inferred in turn. Disadvantageous in this technology is the strong dependence of the sound velocity, and therefore of the measurement result, from the prevailing temperature and humidity. In addition, such ultrasound sensors have a large blind range, in which no reliable measurement is possible due to an overlap of the emitted and the reflected sound signals. This blind range is located near to the sound sender or sound receiver. A significant minimum distance between the sound senders or sound receivers and the uppermost coin of a coin stack is in practice necessary for a reliable measurement, for instance a distance of around 2 cm. In turn, this limits the capacity of the coin tubes when the installation space of the device is given.
Moreover, the utilization of image processing systems is known for identifying and counting tokens used for instance in gambling casinos. Insofar, examples here are U.S. Pat. No. 6,425,817 B1, U.S. Pat. No. 6,626,750 B2, U.S. Pat. No. 7,481,702 B2 or US 2014/0200071 A1. Some of these documents describe imaging methods in which a lateral view of a stack of tokens is captured. Based on this principle, an image processing software identifies different tokens located in the stack and determines an overall value of the stack, for instance of a gambler of a gambling casino. The described methods require a lateral access of the image sensors to the tokens that are to be evaluated. Such a lateral access is not always given in practice. Moreover, the described image evaluation systems are complex and not always reliable for this reason.